A Late Quaternary palynological and sedimentological record from two coastal swamps at southern Kaitoke, Great Barrier Island, New Zealand

Abstract

Pollen and sediment analyses of two cores from southern Kaitoke (Forsythes' Paddock and Blackwells' Bush), Great Barrier Island, show that at c. 7500 cal. yr B.P., the area was an estuary with tidal flats and Avicennia. By c. 3000 cal. yr B.P., a Restionaceae (Leptocarpus) salt marsh had developed in the estuary as marine influences lessened. By c. cal. 2550 yr B.P., fresh water swamp (Cyperaceae-Gleichenia-Leptospermum) had replaced the salt marsh. Conifer-hardwood forest surrounding the southern Kaitoke sites from c. 7500-c. 2800 cal. yr B.P. was dominated by Dacrydium, Metrosideros and Libocedrus. After c. 2800 cal. yr B.P., Metrosideros was replaced by Agathis, Phyllocladus and Prumnopitys taxifolia, suggesting climatic change to more variable conditions. The presence of the Kaharoa Tephra suggests that major Polynesian deforestation at southern Kaitoke began c. 600 cal. yr B.P. Minor pre-Kaharoa fire disturbance is evident c. 1750 cal. yr B.P. and c. 1290-970 cal. yr B.P.